UI: Dashboard tweaks (#5974)

- Don't show divider below heatmap when it's hidden via media-query
- Make divider between user menu adhere to container width
- Remove excessiv margins on heatmap

public/less/_base.less

@@ -601,7 +601,6 @@ footer {
 #user-heatmap {
     width: 107%; // Fixes newest contributions not showing
     text-align: center;
-    margin: 40px 0 30px;
 
     svg:not(:root) {
         overflow: inherit;

templates/user/dashboard/dashboard.tmpl

@@ -4,7 +4,7 @@
 	<div class="ui container">
 		{{template "base/alert" .}}
 		<div class="ui mobile reversed stackable grid">
-			<div class="ten wide column">
+			<div class="ui container ten wide column">
 				{{if .EnableHeatmap}}
 					<div id="user-heatmap" style="padding-right: 40px">
 						<activity-heatmap :locale="locale" :suburl="suburl" :user="heatmapUser">
@@ -12,8 +12,8 @@
 								<div class="ui active centered inline indeterminate text loader" id="loading-heatmap">{{.i18n.Tr "user.heatmap.loading"}}</div>
 							</div>
 						</activity-heatmap>
-					</div>
 						<div class="ui divider"></div>
+					</div>
 				{{end}}
 				{{template "user/dashboard/feeds" .}}
 			</div>